Aging & Health A to Z

Stroke

Causes & Symptoms

All types of strokes involve the interruption of the blood supply to some area of your brain. Both blocked blood vessels and leaking vessels result in a lack of oxygen and nutrients getting to brain cells. It takes only a few minutes—or even seconds—after blood flow is interrupted to kill millions of brain cells. 

Thrombotic or embolic strokes usually means that some areas of your arteries are being damaged by atherosclerosis—a build-up of cholesterol and other fats, combined with calcium— that forms atherosclerotic “plaques”. Atherosclerosis in these areas results in blood clots that can suddenly clog up and block already narrowed arteries. Sometimes the narrowing occurs in the carotid arteries of your neck, stopping the blood from getting to your brain. Rarely, not enough blood can get to the brain because of very low blood pressure, such as when one is in shock. 

Embolic strokes are often associated with an irregular or abnormal heart rhythm in one of the upper chambers of your heart (called an atrium). The abnormal rhythm is called atrial fibrillation.  Atrial fibrillation may cause blood clots to form in your heart. These may travel up to your brain and cause an embolic stroke. 

Intracerebral hemorrhagic strokes are usually caused by uncontrolled high blood pressure (hypertension).  Subarachnoid hemorrhagic strokes are more likely to result from the breaking of a weak area of a blood vessel known as an aneurysm. Often, these weak areas are abnormalities that you are born with.

Risk Factors

Lifestyle factors: Your likelihood of having a stroke is higher if your lifestyle is unhealthy. The following lifestyle factors increase your stroke risk:

• Obesity or being overweight
• A diet high in saturated and trans fats and low in “good” fats
• High salt intake
• Alcohol abuse
• Substance abuse (cocaine and other illegal drugs)
• Smoking. 

Medical factors: Having certain medical conditions or diseases increases your chance of having a TIA or a stroke. These conditions include: 

• Previous stroke or TIA
• High blood pressure (hypertension) (the number one risk factor for stroke)
• Atrial fibrillation
• Diabetes
• Family history of stroke
• High cholesterol
• Older age (the risk increases for people over age 55)
• Race (stroke is more likely to cause death in African Americans)
• Heart disease
• Atherosclerosis
• Peripheral artery disease (PAD) – decreased blood flow, especially in your legs or in the carotid arteries in your neck
• Other circulation problems that are not well-controlled, such as sickle cell anemia
• Anemia that is left untreated. 

Symptoms and Warning Signs

Stroke symptoms vary considerably, depending upon:

• The type of stroke
• The part of the brain that is affected
• The severity of the brain damage. 

Usually, symptoms start suddenly and a disability is evident right away – for instance, weakness or paralysis in some part of the body, with or without a headache. Often, the symptoms get progressively worse over the first hours or days, or the symptoms may come and go. Some people are not even aware that they have had a stroke. In cases of TIA, symptoms may last only a few minutes and go away completely.

The National Stroke Association suggests following the “FAST” guideline below if you suspect that you or someone in your care may be having a stroke: 

FACE:  Ask the person to smile. Does one side of the face droop?

ARMS:  Ask the person to raise both arms. Does one arm drift downward?

SPEECH: Ask the person to repeat a simple sentence. Does the speech sound slurred or strange?

TIME:  If you observe any of these signs, it’s time to call 911 or go to the nearest stroke center or hospital. 

A more complete list of stroke or TIA symptoms is listed below: 

• Dizziness or vertigo (the feeling that you or everything around you is spinning)
• Sleepiness, reduced responsiveness, unconsciousness, or coma
• Changes in sense of touch, and sensations of pressure, temperature, or pain
• Confusion
• Difficulty speaking
• Inability to understand what another person is saying
• Difficulty swallowing
• Vomiting
• Problems with reading or writing
• Vision impairment – double vision, loss of vision
• Problems identifying objects or knowing their functions
• An intense, sudden headache Trouble walking: clumsiness or difficulties with coordination and balance
• Muscle weakness, in face, arm or leg – often only on one side
• Numbness in a certain part of the body.

Updated: March 2012
Posted:  March 2012